Fibre-Based Electrochemical Sensor for Chemical Analyte Detection
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Solution Overview
Problem
Existing methods for detecting chemical analytes in gaseous environments, such as those using conductive polymers and carbon nanotubes, face limitations in sensitivity, selectivity, and mechanical integrity, particularly in high analyte concentrations.
Innovation Solution
A self-supported fibre-based electrochemical sensor with a co-continuous phase blend of carbon nanotubes dispersed in a first polymer phase, which is sensitive to the analyte and soluble in it, and a second phase that is non-conductive and mechanically supportive, allowing for measurable changes in electrical conductivity upon analyte exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conductive polymer composite is used to detect chemical analytes, then the sensor can detect the presence of analytes through swelling-induced resistivity changes, but the mechanical integrity and structural stability of the sensor deteriorate in high analyte concentrations
Solution Approach 1:
The sensor is divided into two distinct continuous phases: a conductive polymer phase (first phase) responsible for analyte detection, and a mechanically supportive polymer phase (second phase) that maintains structural integrity. This segmentation allows each phase to perform its specialized function without compromising the other, resolving the contradiction between detection sensitivity and mechanical strength.
Solution Approach 2:
The invention uses a composite material system consisting of two continuous polymer phases with different properties. The conductive phase provides sensing functionality while the supportive phase provides mechanical strength. This composite structure enables the sensor to simultaneously achieve both analytical performance and structural stability in high analyte concentration environments.
2Measurement precision
If the concentration of carbon nanotubes is increased above the percolation threshold to improve conductivity sensing, then the sensitivity to analyte detection is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Carbon nanotubes are concentrated specifically in the conductive polymer phase rather than being uniformly distributed throughout the entire composite. This local concentration above the percolation threshold ensures high conductivity sensing capability in the phase that contacts the analyte, while the supportive phase remains free of nanotubes, simplifying its manufacturing and processing.
3Speed
If a single continuous polymer phase is used for analyte detection, then the response time is improved, but the selectivity and accuracy of analyte identification deteriorate
Solution Approach 1:
The sensor employs two continuous phases with distinct functions: the conductive phase rapidly responds to analyte presence through conductivity changes, while the supportive phase provides structural stability and can be tailored for selective analyte interaction. This segmentation enables both fast response and accurate identification.
Solution Approach 2:
The invention changes the physical and chemical parameters of the polymer phases to optimize performance. The conductive phase uses parameters (conductive filler concentration, polymer composition) optimized for rapid conductivity response, while the supportive phase uses parameters optimized for mechanical stability and selective analyte interaction, achieving both fast response and high accuracy.
Data Source
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AI summary
The present invention is related to a method for detecting at least one chemical analyte vapour in a gaseous environment comprising the steps of: - providing a fibre-based electrochemical sensor, said fibre-based sensor comprising at least one type of composite fibres, said type of composite fibres comprising a co-continuous phase blend comprising a first and a second continuous polymer phase, the first polymer phase being sensitive to the chemical analyte vapour to be detected in use, wherein said first polymer phase comprises a dispersion of carbon nanotubes at a concentration above the percolation threshold and wherein the chemical analyte is soluble in said first polymer phase; - measuring the initial electrical conductivity of the fibre-based sensor; - bringing said fibre-based sensor into contact with at least one chemical analyte to induce a modification of the electrical conductivity of the fibres; - measuring the modification of the resulting electrical conductivity of said fibre-based sensor and correlating said modification with the identification of the chemical analyte to be detected.